bpo-30822: Exclude tzdata from regrtest --all (#2775)

When running the test suite using --use=all / -u all, exclude tzdata
since it makes test_datetime too slow (15-20 min on some buildbots)
which then times out on some buildbots.

-u tzdata must now be enabled explicitly, -u tzdata or -u all,tzdata,
to run all test_datetime tests.

Fix also regrtest command line parser to allow passing -u
extralargefile to run test_zipfile64.

Travis CI: remove -tzdata. Replace -u all,-tzdata,-cpu with -u all,-cpu since tzdata is now excluded from -u all.

Lib/test/test_regrtest.py

@@ -191,15 +191,26 @@ class ParseArgsTestCase(unittest.TestCase):
             with self.subTest(opt=opt):
                 ns = libregrtest._parse_args([opt, 'gui,network'])
                 self.assertEqual(ns.use_resources, ['gui', 'network'])
+
                 ns = libregrtest._parse_args([opt, 'gui,none,network'])
                 self.assertEqual(ns.use_resources, ['network'])
-                expected = list(libregrtest.RESOURCE_NAMES)
+
+                expected = list(libregrtest.ALL_RESOURCES)
                 expected.remove('gui')
                 ns = libregrtest._parse_args([opt, 'all,-gui'])
                 self.assertEqual(ns.use_resources, expected)
                 self.checkError([opt], 'expected one argument')
                 self.checkError([opt, 'foo'], 'invalid resource')
 
+                # all + a resource not part of "all"
+                ns = libregrtest._parse_args([opt, 'all,tzdata'])
+                self.assertEqual(ns.use_resources,
+                                 list(libregrtest.ALL_RESOURCES) + ['tzdata'])
+
+                # test another resource which is not part of "all"
+                ns = libregrtest._parse_args([opt, 'extralargefile'])
+                self.assertEqual(ns.use_resources, ['extralargefile'])
+
     def test_memlimit(self):
         for opt in '-M', '--memlimit':
             with self.subTest(opt=opt):